A truss of an escalator is installed so as to bridge floors which are separate from each other in a height direction and a horizontal direction. Support fittings each being made of angle steel are provided to both end portions of the truss, and one end portion or both end portions of the truss are supported on the floor in an unfixed state of being slidable in a longitudinal direction of the truss with respect to the floor. In the escalator described above, the support fitting provided on an unfixed side of the truss moves relative to a backup plate provided to the floor. Hence, for example, when an earthquake occurs, generation of a large stress between the truss and the backup plate is prevented. Therefore, when a building shakes in a direction in which a dimension between the floors increases due to the earthquake, the truss is prevented from falling off the floor by sufficiently ensuring an overlap allowance being a length of a portion of the support fitting, which is in contact with the backup plate. Further, when the building shakes in a direction in which the dimension between the floors is reduced due to the earthquake, compression of the truss in the longitudinal direction is prevented by sufficiently ensuring a clearance between the truss and the floor.
The support fittings are members which support a full weight of the escalator. Therefore, when the clearance between the truss and the floor is large, a load exerted on the support fittings increases. Thus, for the truss having one fixed end, which ensures the clearance between the truss and the floor only at one longitudinal end portion of the truss, it is difficult to provide a clearance which is sufficient to cope with a change in dimension between the floors generated at the time of occurrence of a large-scale earthquake. The truss having both unfixed ends, which ensures the clearance between the truss and the floor at each of the both longitudinal end portions of the truss, can cope with a change in dimension between the floors, which is generated at the time of occurrence of an earthquake, with the sum of the clearances between the both longitudinal end portions of the truss and the respective floors, and therefore, can cope with the change in dimension between the floors generated at the time of occurrence of a large-scale earthquake. However, the both longitudinal end portions of the truss are not fixed to the respective floors. Thus, even at the time of occurrence of a small-scale earthquake, the escalator is positionally shifted with respect to the floors.
Therefore, hitherto, there has been known an escalator including a pivot support member provided upright on the backup plate and the support fitting fixed to the truss, which are engaged with each other, which copes with the change in dimension between the floors by breakage of the pivot support member at the time of occurrence of a large-scale earthquake (see, for example, Patent Literature 1).